1. Field of the Invention
The present invention is generally concerned with the attaching of any kind of object to any kind of support.
It is more particularly directed to the case where the object to be fastened is a channel of the kind routinely used to guide electrial conductors in electrical equipment cabinets, that is cabinets or cases used to accommodate any form of electrical equipment.
2. Description of the Prior Art
As is known, a channel of this kind, which may be made from a synthetic material, for example, conventionally has a generally U-shaped transverse cross-section with, along the axis of its bottom, at regular intervals defined by applicable standards, openings adapted to permit the passage of fastening members needed to attach it to a support of some kind.
More often than not these openings along the axis of the bottom are elongate slots, in particular to permit a limited degree of adjustment of the position of the channel relative to the support to which it must be attached.
The electrical equipment is accommodated in the cabinet and to this end there is first installed in the latter an appropriate dedicated support.
This may consist, for example, of a perforated plate, by which is meant a plate, generally of metal, formed with an array of holes, of rectangular contour in practice, separated from one another in one direction by crossmembers and in a second direction, orthogonal to the first, by bars.
Currently, a channel is attached to perforated plate of this kind more often than not using screws or rivets.
Such devices have usually to be taken from a bulk storage bin and this can result in costly time-delays and losses through clumsiness.
When screws are used, whether of metal or of a synthetic material, after being passed through the bottom of the channel and the perforated plate they must cooperate with a nut on the other side of the perforated plate.
Fitting them thus necessitates working behind the perforated plate and in practice this operation can be lengthy and awkward.
There has been made provision to attach them to the perforated plate in advance, by means of appropriate clips.
However, as the facility for adjusting the position of the channel is limited, costly fumblings remain inevitable.
The same applies to rivets, the use of which further involves the use of a special tool.
Finally, when such devices, whether screws or rivets, are of metal, they normally contravene the usual safety requirements since they result to some extent in the establishing of a metal bridge between the electrical conductors contained in the channel and the underlying perforated plate, to the detriment of the continuous insulation normally ensured by the bottom of a channel of this kind when of a synthetic material.
French Patent Application No. 78 02643 filed Jan. 31 1978 and published under the number 2 416 577 describes a fastening device which is used to attach a channel to a perforated plate and eliminates to a certain degree the disadvantages outlined hereinabove.
However, as this fastening device forms a variety of stirrup-shaped bracket of which the side members must encircle the flanges of the channel to be attached, engaging with these flanges snap fastener fashion by means of the slots which they usually feature for the electrical conductor(s) concerned to pass through, they are suitable only for specific channels, as their dimensions must be adapted to those of the latter.
Thus this is a fastener device of highly limited practical utilization.
Also, competing with electrical equipment cabinets equipped with a perforated plate are electrical equipment cabinets which, for supporting the electrical equipment which they are designed to contain, are equipped with a chassis formed by two uprights at the sides to which are attached transversely along their height profiled members, generally of metal, appropriate to the supporting function.
These profiled members generally have a generally U-shaped transverse cross-section, the flanges having the edges bent through a right angle to form rims for snap action engagement with the electrical equipment concerned, whether the flanges are of the same height, in which case the rims are usually outwardly directed, or of unequal height, in which case the rims are usually directed inwards.
Although such profiled members are well-suited to the fastening of electrical equipment, the same does not apply to the channels designed to accommodate the electrical conductors serving the equipment.
Apart from the very necessity for profiled members of this kind in order to support the channels, these members must be provided with adapter members to enable the channels to be attached to them.
As this attachment is effected using screws or rivets, as previously, and with screws more often than not in practice, the same disadvantages as described hereinabove result, in particular those of hesitation, clumsiness and fumbling.
Also, independently of the electrical equipment accommodated in the electrical equipment cabinet concerned, the door of the cabinet is usually equipped on the front with electrical components such as lamps, pushbuttons, switch levers and other display and/or control devices, connected to electrical conductors which must be routed along the length of the door.
Although certain of these conductors may be bound up with others by means of cable ties to constitute relatively rigid assemblies able to retain of themselves a stable configuration in contact with the door, without untidy or random routing of the conductors relative to the door, this does not necessarily apply to all the conductors and it is more often than not necessary to fasten them to the door for their protection and so that they are not inadvertently subject to tensile forces which may result in them being pulled off, given that they are to a greater or lesser extend in the way when the cabinet door is opened.
However, it is conjointly necessary to maintain the integrity of the door, for security and sealing reasons, which rules out the making of any holes in the door for the purposes of the necessary fastening, only holes which are indispensible to the fitting of electrical or other components to the door being permitted.
Currently, the electrical conductors connected to these components are more often than not bonded to the door, through the intermediary of either appropriate self-adhesive base members, the adhesion of which to the door is in practice mediocre, or appropriately bonded channels, the adhesion of which is satisfactory but which require a relatively complex gluing operation to install them.
It is also possible to fix uprights to the door along its edges adapted to enable the attachment of a profiled member to which a channel of this kind may be attached, to enable the channel to be fastened to a cabinet door.
However, apart from the necessity to use uprights and a profiled member in this case, the attachment to the latter of a channel necessitates as previously adapter members with the disadvantages specified hereinabove.
French Patent Application No. 81 21729 filed Nov. 18 1981 and published under the number 2 516 713 proposes to attach a channel to an electrical equipment cabinet door by profiting from one of the holes already made in the door for the installation of electrical or other components which it must carry.
To this end use is made of a fastening lug which features a passage enabling it to be attached to the door concerned by being clamped between the two parts which an electrical component to be attached to the door usually comprises. The lug also features a threaded hole for fastening a channel.
With a fixing lug of this kind a channel is fitted by means of screws, with all the disadvantages inherent to this method of fastening, as outlined hereinabove.
Also, in this case, the electrical components to be attached to the door must be disposed according to the intervals between the openings in the bottom of the channel, which may be unduly constraining.
In all cases, whether a channel is to be attached to a perforated plate or to a profiled member or to an electrical equipment cabinet door, independently of the specific disadvantages inherent to each of these supports, there is a risk of fumbling on fitting a channel given, on the one hand, the limited extent of the openings in the bottom of the channel enabling only limited adjustment of its position relative to the support and, on the other hand, the fact that it is more often than not necessary to manipulate the channel and the support virtually simultaneously.
These disadvantages are circumvented using the fastening base member which is described in French Patent Application No. 82 21807 filed Dec. 27 1982 and the first Patent of Addition Application thereto filed on Sept. 16 1983 under the number 83 147458.
However, this fastening base member is suitable only for attaching a channel to a profiled member, for which purpose it is specifically designed
It may not be used to effect fastening to a perforated plate or to an electrical equipment cabinet door or to a chassis upright.
A general objective of the invention is to provide a system which eliminates the disadvantages of the usual forms of fastening device and confers additional advantages, being usable equally well in a fastening device for attaching a channel to a perforated plate or to an electrical equipment cabinet door or to a chassis upright.